Miso is a fermented paste that adds a salty umami flavor. Most miso is made in Japan, where the ingredient has been used since the eighth century or earlier.
The paste, similar in texture to peanut butter, is typically a cultured mixture of soybeans, salt, and koji (a mold). Depending on the variety, miso can be smooth or chunky and is fermented anywhere from a few weeks to several years
Although miso is traditionally made from soybeans, certain varieties use other types of beans or peas. Other ingredients may also be used to make it, including rice, barley, rye, buckwheat and hemp seeds, all of which affect the color and flavor of the final product.
Miso contains a good amount of vitamins, minerals and beneficial plant compounds. One ounce provides you with:
- Calories: 56
- Carbs: 7 grams
- Fat: 2 grams
- Protein: 3 grams
- Sodium: 43% of the RDI
- Manganese: 12% of the RDI
- Vitamin K: 10% of the RDI
- Copper: 6% of the RDI
- Zinc: 5% of the RDI
It also contains smaller amounts of B vitamins, calcium, iron, magnesium, selenium and phosphorus, and is a source of choline. Varieties made from soybeans are considered to be sources of complete protein because they contain all the essential amino acids needed for human health.
Miso is also very salty, so if you are watching your salt intake, use sparingly.
The fermentation process used to produce miso makes it easy for the body to absorb the nutrients it contains. The fermentation process also promotes the growth of probiotics, beneficial bacteria that provide a wide array of health benefits. A. oryzae is the main probiotic strain found in miso. A healthy gut flora is very important because it helps defend your body against toxins and harmful bacteria. It also improves digestion and reduces gas, constipation and antibiotic-related diarrhea or bloating
A. oryzae is the main probiotic strain found in miso. Research shows that the probiotics in miso might help reduce symptoms linked to digestive problems including inflammatory bowel disease (IBD). The fermentation process also helps improve digestion by reducing the amount of anti-nutrients in soybeans. Anti-nutrients are compounds naturally found in foods, including in the soybeans and grains used to produce miso. If you consume anti-nutrients, they can bind to nutrients in your gut, reducing your body’s ability to absorb them.
Observational studies have found a link between high-salt diets and stomach cancer. However, despite its high salt content, miso doesn’t appear to increase the risk of stomach cancer the way other high-salt foods do.
One study compared miso to salt-containing foods such as salted fish, processed meats and pickled foods. The fish, meat and pickled foods were linked to a 24-27% higher risk of stomach cancer, whereas miso wasn’t linked to any increased risk. Experts believe this may be due to beneficial compounds found in soy, which potentially counter the cancer-promoting effects of salt.
Animal studies also report that eating miso may reduce the risk of lung, colon, stomach and breast cancers. This seems especially true for varieties that are fermented for 180 days or longer. Miso fermentation can last anywhere from a few weeks to as long as three years. Generally speaking, longer fermentation times produce darker, stronger-tasting miso.
Regular miso consumption may reduce the risk of liver and breast cancer by 50-54%. The breast-cancer protection appears especially beneficial for postmenopausal women.
Miso is also rich in antioxidants, which may help guard your body’s cells against damage from free radicals, a type of cell damage linked to cancer.
Miso contains nutrients that may help your immune system function optimally. The probiotics in miso may help strengthen your gut flora, boosting immunity and reducing the growth of harmful bacteria. A probiotic-rich diet may help reduce your risk of being sick and help you recover faster from infections, such as the common cold.
Other health benefits from including miso in your diet:
- May promote heart health: Miso soup may reduce the risk of death from heart disease.
- May reduce cholesterol levels: Animal studies show that miso may help reduce levels of LDL cholesterol in the blood.
- May reduce blood pressure: Miso appears to reduce blood pressure in animals.
- May protect against type 2 diabetes: Some studies show that fermented soy products such as miso may help delay the progression of type 2 diabetes. (Not all studies agree on this.)
- May promote brain health: Probiotic-rich foods such as miso may benefit brain health by helping improve memory and reducing symptoms of anxiety, stress, depression, autism and obsessive-compulsive disorder (OCD)
Miso consumption is generally safe for most people. Most varieties are made from soybeans, which could be considered a goitrogen. Goitrogens are compounds that may interfere with the normal functioning of the thyroid gland, especially in those who already have poor thyroid function.When goitrogen-containing foods are cooked and consumed in moderation, they are likely safe for all individuals, even those with thyroid problems.
How to Buy
When shopping for miso, you may find it called “miso paste” or “soybean paste.” Look for miso in plastic tubs or jars in Asian grocery stores or the refrigerator section of your local health food store. Some large grocery stores stock miso in plastic tubs near the refrigerated tofu.
Look for miso with a short ingredient list, free of stabilizers and preservatives.
There are more than 1,000 types of miso, ranging in texture, flavor, and color. These factors can be influenced by the ingredients, length of fermentation, and the conditions under which the miso is kept. Miso imported into the United States is typically divided into two main categories: light or white miso and dark or red miso. Some miso is labeled awase, which is a mixture of more than one kind of miso paste
White or light miso (sometimes called sweet miso) can be light beige to yellow in color and tends to be lighter and sweeter in flavor thanks to a shorter fermentation time. It’s made with less soybean content and more grains, like white rice. Red or dark miso ranges in color from light brown to almost black and is fermented for longer for a stronger, funkier, and saltier flavor. This miso is made with a higher proportion of soybeans and salt for an intense experience.
Different types of miso can often be used interchangeably in recipes but with varying results. Generally, the darker the color, the stronger the taste. Light-colored miso is better for light dressings and sweets, while dark miso is best for stews.
While the miso selection is somewhat limited in the U.S., a dizzying variety is available in Japan, with different regions specializing in different types of miso. Varieties like Hatcho (a dark miso) and genmai (made with brown rice) can sometimes be found stateside.
How to Store
Since it’s a fermented product, miso keeps very well. Store it tightly sealed in the original container in the refrigerator and it will keep for a year or longer. Light miso doesn’t have the shelf life of the darker varieties, since it had a shorter fermentation time, and should be used in under a year. Miso does oxidize, so placing a piece of wax wrap directly against the paste after each use will help prevent discoloring.
How to Cook
Miso is a paste and can be mixed into sauces, dressings, batters, and soups. It can be eaten cooked or raw. Since miso is a cultured food, it’s best to add it to long-cooked dishes at the end of cooking. Be careful not to boil dishes like miso soup because too much heat will kill the active bacteria in the miso.
You can also blend it with ingredients such as peanut butter, tofu, lemon or apple juice to make dipping sauces or spreads. When combined with oil and vinegar, it makes a simple and tasty salad dressing.
Miso is ready-to-use right out of the container, and while it is typically not eaten alone, it does not need further preparation.
The most common use of miso is in Japanese-style miso soup, a traditional dish that’s eaten for breakfast and as a part of other meals. Miso also adds a unique burst of flavor to marinades, gravy, other soups like udon or ramen, or vegetable and tofu dishes.